1. Field of the Invention
This invention generally relates to a linear motion guide unit suitable for use in moving parts of various machines and apparatuses, and, in particular, to a height-reduced linear motion guide unit.
2. Description of the Prior Art
A typical example of a prior art linear motion guide unit for use in moving parts of various devices is illustrated in FIG. 2 of Japanese Pat. Laid-open Pub. No. 61-136018. However, as shown in FIG. 5 of this application, this type of linear motion guide unit is fixedly mounted on a housing A of a device by tightely securing its bed B thereto using a bolt C. The bed B has a generally U-shaped cross section and it is mounted on the housing A with its bottom wall portion in contact with the housing A. A sliding table E also having a generally U-shaped cross section is received in a space defined by the bed B, and a plurality of rolling members D are interposed between the bed B and the sliding table E so that the sliding table E can move relative to the bed B and thus to the housing A along a straight path back and forth. Such a linear motion guide unit is commonly used in the moving parts of such devices as floppy disc drives and hard disc drives.
The prior art linear motion guide units typically have a relatively large height H from a surface F of a housing A to a top surface G of a sliding table, as indicated in FIG. 5, on the order of approximately 7 mm at minimum. However, there has been a need to reduce the height of such a linear motion guide unit, first, to allow a high degree of flexibility in the design of such devices as floppy disk drives and had disc drives, and second to increase the scope of linear guide motion unit application, such as, for instance, use the high precision measuring devices.